Copy deep vs shallow
Predict and write a function that returns a copied list and inspect whether nested modification affects the original.
Minimum Genetic Mutation
Implement a function to compute the minimum number of single-character mutations needed to transform one gene string into another, using a given bank of valid mutations.
Permutation Generator
Write a function that returns all permutations of a list of distinct integers.
Permutations
Write a function that returns every permutation of the elements in the input list.
Permutations II
Return all distinct permutations of a list of integers that may include duplicates.
Letter Tile Possibilities
Given a string of letter tiles, count the number of distinct non-empty sequences that can be formed using any non-empty subset in any order.
Beautiful Arrangement Count
Count the number of permutations of 1..n such that for every index i, either i is divisible by the number at that position or the number is divisible by i.
Permutation in String
Determine if any permutation of a shorter string appears as a contiguous substring in a longer string using an efficient sliding window.
Showing 1–8 of 8 challenges
Guide: free Python coding challenges
Practice Python by solving problems
PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.
How to use the arena
- Pick a category — basics, algorithms, strings, and more
- Open a challenge, read the statement, and edit the starter code
- Run tests, fix failures, then try a related quiz or tutorial lesson
Challenges vs tutorials and quizzes
Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.